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Izuku had rebuilt his life around not thinking about Katsuki Bakugou, and he'd gotten good enough at it that he almost believed the reconstruction was permanent — right up until his boss slid a client file across the workbench with a name on it that made every carefully laid brick come down at once.
"Dynamight's agency," Yaboku said, oblivious to the way Izuku's hands had gone still over his soldering iron, the faint smell of flux still curling up between them. "They asked for you specifically. Apparently his last three support engineers couldn't keep his gear from disintegrating under actual combat load. Somebody recommended you."
"Somebody," Izuku repeated, in a voice that came out steadier than he felt.
"You know him?"
"We grew up together." Four words doing an enormous amount of quiet, careful work. "It's been a long time."
He turned the file over in his hands after Yaboku left, thumb tracing the edge of it without opening it, like the paper itself might still be hot from wherever it had come from.
He knew the name printed on the tab already. He didn't need to open it to know the shape of the man attached to it — the sharp angles of him, the volume, the way a room used to rearrange itself around Katsuki Bakugou whether it wanted to or not.
He took the case anyway. He'd built a career on being the engineer who could handle the jobs nobody else wanted — the heroes with quirks that shredded conventional gear within a month, the ones support companies quietly stopped taking calls from.
He wasn't going to turn one down because it came with history attached. That would mean the history still had power over him, and he'd worked too hard, for too many years, to let that be true.
He told himself that the whole train ride to the agency, watching the city blur past the window, rehearsing a version of professional composure he hoped would hold.
He was still telling himself that when the workshop door slid open and Katsuki Bakugou walked in — hero costume scuffed at the knee, one gauntlet visibly cracked along a seam, scowling like the world owed him a written explanation for its continued existence.
The scowl faltered. For exactly one second, something in his face went completely unguarded, boyish, almost young again, before it slammed back down into something more careful.
"Deku."
"It's Midoriya, actually. Professionally." Izuku kept his voice level and his hands busy laying out diagnostic cable, because if he let them go still he thought he might do something humiliating — laugh, or cry, or both at once. "Your agency requested a support consult. That's me, apparently."
"They said they got the best guy in the business." Bakugou's eyes narrowed, doing the same rapid, restless calculation Izuku remembered from a decade of shared classrooms — recalculating, recalibrating, refusing to let his face show the work underneath it. "Didn't say it was gonna be you."
"Is that a problem?"
A long pause stretched out between them, long enough that Izuku almost filled it out of old habit, the way he used to fill every silence Bakugou left hanging, just to keep some fragile peace intact.
He didn't fill it this time. He made himself wait, hands still, breath even.
"No," Bakugou said finally, rough, like the word cost him more than he wanted to admit out loud. He set the cracked gauntlet down on the bench between them, a kind of offering. "Show me what you've got."
Izuku didn't go home after that first session. He went, instead, three train stops out of his way, to a workshop that smelled permanently of solder and ozone and something faintly, dangerously combustible, where Mei Hatsume was upside-down under a workbench, swearing at a servo motor.
"If you're here to borrow my calibration rig again, the answer's yes, but you owe me actual dinner this time, not the convenience-store onigiri you tried to pass off as payment last month." She didn't bother looking up. She never had to; she'd clocked his footsteps from the hallway years ago and stopped needing visual confirmation.
"I'm not here for the rig." Izuku dropped his bag by the door and sat down on the one stool in her workshop that wasn't currently supporting some half-finished invention, a spot that had been, by unspoken agreement, his for the better part of a decade.
Something in his voice made her actually surface, goggles pushed up into her frizzy hair, grease smudged along one cheekbone. She studied his face for a second with the same sharp, unfiltered attentiveness she gave a malfunctioning prototype.
"Okay, that's your 'something happened' voice. Spill."
"I got a new client today." He picked at a loose thread on his sleeve instead of looking at her directly. "Dynamight's agency."
Mei's whole posture changed — she pulled herself the rest of the way out from under the bench and sat up properly, giving him her full attention, which from Mei was a rarer commodity than most people realized. "Dynamight. As in—"
"As in Kacchan, yeah."
"Kacchan." She said the old nickname like she was testing whether it still had teeth. "The Kacchan. The one you haven't talked about in — what, since middle school? The one whose name you very deliberately don't bring up, ever, in a way that is extremely obvious to anyone who's known you for twelve years?"
"That's the one."
"And he requested you? By name?"
"He didn't know it was me until I walked in. His agency just heard I was good." Izuku exhaled, long and unsteady. "I almost turned it down. I told myself I wasn't going to, because turning it down would mean it still mattered, and I've spent nine years trying to get to a place where it didn't matter."
"you sure it doesn’t matter?"
He didn't answer right away. Mei, to her credit, didn't fill the silence either — she just waited, wrench loose in one hand, giving him the same patient, undemanding space she'd been giving him since they were fourteen years old picking through scrap metal on a beach neither of them had actually cleaned.
"He apologized. Sort of. For a second I thought he was going to, and then he just — showed me a busted gauntlet instead, like that was easier." Izuku laughed, short and a little wrecked. "It's stupid, Mei. It's been nine years. I built a whole career, I built a whole life, I'm not supposed to still feel like I got hit by a train because he said four words to me."
"First of all, feelings aren't an engineering spec, they don't care whether you think they're 'supposed' to still be there." Mei set the wrench down and leaned forward, elbows on her knees. "Second of all — and I say this with love, Izuku, the kind of love that comes from watching you build objectively incredible hero gear for nine straight years while going home to an apartment with exactly one photo on the wall that's not of a quirk diagram — you have never once, in the entire time I've known you, stopped caring about that idiot. You just got very, very good at building things so complicated that you didn't have time to notice."
"That's an oddly precise read for someone who claims she doesn't 'do' emotional nuance."
"I don't do emotional nuance in myself. I'm an excellent outside observer." She grinned, sharp and fond. "So what are you gonna do?"
"My job. Professionally. Competently." He said it like a plan, like reciting it would make it true. "Fit his gear. Keep it civil. Not — whatever this is."
Mei looked at him for a long moment, the kind of look that saw straight through a cover story to the actual blueprint underneath.
"Uh-huh," she said, entirely unconvinced, and swiveled back toward her workbench like the matter was settled, which — knowing her — meant she considered the conversation only temporarily paused.
"You want me to build you an excuse to avoid this like a coward, or you want me to build you the confidence to actually deal with it? Because I can engineer either, but only one of them is going to make you stop looking like you got hit by a train every time his name comes up."
"I didn't come here for a life consultation."
"You came to the one person who's watched you not-talk-about this for nine years and told me the whole thing unprompted the same day it happened." Mei didn't even glance up from the servo motor she'd gone back to disassembling. "That's not a coincidence, Midoriya. That's a cry for help with extra steps."
He didn't have a good comeback for that. He sat with her a while longer instead, in the familiar noise of her workshop, letting the ordinary rhythm of an old friendship do what it always did — make the unmanageable feel, if not resolved, at least survivable.
What Izuku had, as it turned out, was better than anything Bakugou's previous three engineers had managed combined, and it took exactly one live-fire diagnostic for Bakugou's scowl to shift from general hostility into something more specific — the particular, furious respect of a man realizing he'd underestimated something and hated being wrong about it.
"How the hell did you calibrate the heat dispersal that tight," Bakugou demanded, turning the gauntlet over in his hands like it might reveal its secrets under enough scrutiny. Sweat still clung to his temple from the test run; the training room behind him still smelled faintly of scorched air. "My last guy said this was a physical limit."
"Your last guy was wrong. He was optimizing for a static output. Your quirk doesn't work statically, it scales — so I built the dispersal to scale with it instead of fighting it."
Izuku pulled up the readout on his tablet, angling it so Bakugou could see the curve. He couldn't quite keep the pride out of his voice; he'd stopped apologizing for being proud of his own work a long time ago. "It's not magic. It's just actually looking at the problem instead of applying the same solution to every hero who walks in the door."
"...Huh." Bakugou looked at him for a second too long, something recalculating behind his eyes. "You got good."
"I was always good."
"Yeah," Bakugou said, quiet, almost like it surprised him to say it out loud. "I know."
It didn't stop there. A second fitting came a week later — routine, on paper, an adjustment to the gauntlet's grip plating — and turned, somewhere in the second hour, into an argument about whether Bakugou's habit of running gear past its rated tolerance in the field counted as bravery or idiocy.
"It's not idiocy if it works," Bakugou snapped, flexing his fingers inside the half-finished glove.
"It's idiocy that happens to work so far." Izuku didn't look up from the soldering point he was refining. "You know how many heroes I've fitted for who said the exact same thing right up until the gear failed mid-fight? I'm not building you something that flatters your ego, I'm building you something that doesn't kill you."
"You used to just agree with everything I said."
"I used to be twelve and scared of you. I'm neither of those things anymore." He finally glanced up, steady, unflinching in a way that made something shift, briefly, in Bakugou's expression. "You want gear that survives you. I'm the only engineer telling you the truth about what that costs."
Bakugou didn't have a retort for that one. He just sat there, flexing the half-finished glove, looking at Izuku like he was seeing an entirely new person wearing a familiar face — which, Izuku supposed, wasn't far from the truth.
The apology came three weeks after that, in pieces, the way Bakugou brought up anything difficult — sideways, angry at himself for having to say it at all.
"I was a piece of shit to you," he said, apropos of nothing, while Izuku was elbow-deep in the wiring of a fresh gauntlet. "Back then. About the quirk thing."
Izuku didn't look up. If he looked up, this would become a bigger moment than either of them could survive standing through.
"Yeah," he said. "You were."
"You still ended up better than every hero-course engineer I've worked with."
"That's not really an apology."
"I know." A long breath, audible even over the whir of the calibration rig. "I'm working up to it."
"Take your time," Izuku said, and meant it, and felt something in his chest loosen for the first time in nine years.
The actual apology, when it finally landed — weeks later still, gruff and incomplete and entirely sincere, delivered while Bakugou stared fixedly at a diagnostic screen instead of at him — didn't fix everything.
But it was real, and Izuku had learned enough, in the years since, to recognize the difference between an apology that cost something and one that didn't.
Underneath all of it, unspoken and increasingly hard to ignore, was the thing neither of them mentioned out loud: a specific, charged awareness that had nothing to do with old friendship and everything to do with what they were.
Izuku caught himself cataloguing things he had no professional business cataloguing — the low, banked heat of Bakugou's scent when he leaned in too close to check a readout, the way his own pulse did something complicated and involuntary whenever Bakugou got frustrated and stopped bothering to keep his volume down.
He suppressed it, thoroughly and professionally, the way he suppressed most inconvenient things about his own biology. He had a career. He had a reputation for being unshakeable under pressure. He was not going to let nine years of careful rebuilding come apart because of his own quirk-adjacent hormones.
He was, in the end, entirely wrong about how much control he actually had over that plan.
It hit on a Thursday, three weeks after the apology, during a late fitting session that had run past midnight because Izuku had been putting off his own medical appointments for months in favor of client deadlines — a habit he'd never quite broken, the same one that used to worry his mother, the same one his suppressant regimen had been quietly, precariously compensating for.
He felt it start as a low warmth he initially mistook for exhaustion — a heaviness behind his eyes, a flush he blamed on the workshop's bad ventilation.
By the time he recognized it for what it actually was, it was already too late to leave gracefully. His legs had gone unsteady under him. His skin felt too sensitive under his own clothes, every seam and edge of fabric suddenly unbearable. His whole body was sending up flares that no amount of professional composure was going to override.
"Midoriya?" Bakugou's voice, from across the workshop, sharpened immediately. "You're—" He stopped. Went very still, nostrils flaring slightly, his pupils doing something Izuku recognized dimly from every half-listened-to biology class he'd ever sat through. "You're in heat."
"I noticed." Izuku's voice came out thinner than he wanted, one hand braced against the workbench to stay upright. "Suppressants failed. I— I should go, I can call someone—"
"It's midnight. You can barely stand." Bakugou hadn't moved from across the room, and Izuku understood, distantly, through the fog starting to press in at the edges of his thinking, that this was a deliberate distance — Bakugou putting space between them on purpose, giving him room to think, giving himself room to think. "I'm not letting you walk out of here like this. I'll call you a car. I'll stay on the other side of the room. Whatever you need."
It would have been so easy for this to go a different way.
Izuku understood that too, in the same distant, clear-eyed part of his brain that hadn't gone under yet — that there was a version of this moment where an alpha didn't ask, where consent got treated as optional in the fog of biology.
Bakugou wasn't doing that. He was standing across the room, jaw tight, every line of him visibly fighting his own instincts, giving Izuku room to choose.
That, more than anything else — more than the heat itself, more than nine years of quiet longing he'd never let himself name — was what made Izuku's next words come out honest instead of just chemical.
"I don't want you on the other side of the room," he said.
Bakugou went very still. "Deku—"
"I mean it. Not because of—" Izuku gestured, helplessly, at his own overheated skin. "Not just because of this. I've wanted this since before I even knew what wanting it meant. I want to choose it with you actually here, not just — not just biology deciding for me."
"If we do this," Bakugou said, low and rough, still not moving, "it's not a one-time thing. Not for me. I'm not doing this and then going back to pretending I don't—"
"I don't want you to pretend either."
That was the last careful, deliberate sentence either of them managed for a while.
What followed was slower than the heat wanted it to be — deliberate in a way that mattered more than either of them said out loud.
Bakugou crossed the room like he was crossing something much larger than a few meters of workshop floor, checking in with a steadiness that had nothing to do with his usual volume — this okay, tell me if it's not, still with me — and Izuku answering honestly every time, both of them choosing this again at every single point where choosing it was possible.
It was warmth and closeness and the particular unraveling relief of finally not having to hold something back anymore — hands finding old, familiar shapes made new, breath shared close enough that neither of them had to say the things they'd spent years not saying, because their bodies were finally saying it for them.
It ended, hours later, in exhausted tangled quiet on the workshop's spare cot, Izuku's head tucked against Bakugou's chest, both of them too wrung out for words and not needing any.
Bakugou didn't mark him that night.
Izuku noticed — the deliberate restraint of it, the choice not to make a permanent decision in the middle of a heat-fogged night, no matter how much either of them might have wanted to. It told him more about how seriously Bakugou was taking this than anything he could have said out loud.
What came after wasn't easy happiness handed to them on arrival — it was harder than that, and more real for being hard.
They had nine years of silence to account for, old wounds that didn't close just because a single night had happened.
There were real fights. One, two weeks in, over Izuku's habit of skipping meals during deadline crunches — Bakugou showing up unannounced at the workshop with takeout, only for Izuku to snap at him for "hovering," and Bakugou snapping right back that he wasn't going to just stand by and watch Izuku run himself into the ground the way he apparently had been for years before Bakugou ever noticed.
It ended with both of them too raw to keep shouting, sitting on the workshop floor eating cold gyoza in silence until Izuku finally said, quietly, "I'm not used to anyone caring if I eat," and Bakugou, just as quietly, said, "Get used to it."
There were smaller moments too, accumulating the way trust always does — in specifics, not declarations.
Bakugou learning Izuku's coffee order without being told twice. Izuku learning that Bakugou's silences after a hard patrol weren't hostility, just exhaustion looking for a safe place to land, and staying anyway instead of retreating the way he used to.
Bakugou standing a little too close in the workshop in ways that weren't about biology anymore, just about wanting to be near, and Izuku letting himself lean into it instead of second-guessing whether he'd earned it.
Six months in, on an evening neither of them would later be able to fully reconstruct the specifics of — just that it was raining, and the workshop lights had been low, and Izuku had been halfway through explaining a modification he was excited about when Bakugou stopped listening to the technical details and just started looking at him instead — Bakugou said, without any of his usual deflection:
"I want this to be permanent. Not because it's convenient. Because I choose you. Every version of you — the kid I was awful to, the guy who builds gear better than anyone I've ever worked with. All of it."
Izuku's hands, mid-gesture, went still. "That's the least deflected I've ever heard you say anything."
"Don't make it weird."
"I'm allowed to make it weird. You just said something borderline poetic."
"Shut up." But he was smiling when he said it — the real one, unguarded, the one Izuku had spent nine years missing without ever quite letting himself admit it.
The bonding happened on a night neither of them tried to make dramatic — no grand gesture, no audience, just the two of them, a year and a half of rebuilding behind them and no more uncertainty about what they wanted ahead of them.
"You sure?" Bakugou asked, one more time, forehead resting against Izuku's, giving him every last chance to say no.
"I've been sure since I was ten years old and didn't have the words for it yet," Izuku said. "Yes. I'm sure."
It was quiet, after that — quiet and slow and entirely theirs, none of the fog of that first frantic night, just two people choosing each other with total clarity. The mark, when it came, was gentle, deliberate, more promise than instinct. Izuku felt it settle into something steady in his chest, a decade of complicated history finally resolving into something simple: chosen, and choosing back.
"Nine years," Izuku murmured, much later, tracing the new mark with careful fingers, still a little disbelieving that it was real. "It took us nine years."
"We got there," Bakugou said, pulling him closer, gruff and certain and entirely unbothered by how long the road had been. "That's what matters."
Izuku, finally, fully at peace with a version of his life he'd once thought was permanently closed off, found he couldn't argue with that.